Colour of sugar is its most important commercial attribute, be it raw or white or refined. Impurities present in liquor are major source of color in the final crystalline product. Therefore, colour of sugar crystals depends on the process used to clarify the raw juices and remove impurities. Better the clarification of the sugar juice better will be the final sugar. Color levels up to 10,000 to 20,000 ICUMSA color units are often obtained after the clarification stage.
The millers and refiners spend huge resources to comply the market requirements on the colour of their product.
Sugarcane and beet juice is an extremely complex liquid containing many organic and inorganic constituents in soluble, suspended and colloidal form. Sugarcane juice has always been considered non-filterable because of the presence of highly gelatinous impurities and colored bodies in it.
Normally clarification process used for sugarcane juice has the following essential steps:    1. Sugar cane juice is limed so as the pH of the juice increases from an initial range of 5.0-6.5 to about 6.8-7.5 followed by heating.    2. After liming, chemicals are further added to juice to enhance the coagulation of the impurities. Coagulation is very important in achieving good end product.    3. Coagulation is followed by evaporation and crystallization.    4. Final clarified product is obtained in the form of high quality of the sugar crystals.
Clarification process removes impurities other than sucrose and thus minimizes loss of sucrose.
Currently used clarification methods include:
    a) Cold liming b) Hot liming c) Fractional liming d) Fractional liming with double heating e) Double sulphitation f) Carbonation g) Ion exchange h) Defeco-melt process i) SAT process